Powered surgical devices including strain gauges incorporated into flex circuits

ABSTRACT

A surgical device includes an end effector and a handle assembly operably coupled to the end effector. The end effector includes an anvil assembly and a cartridge assembly pivotally coupled to one another. The cartridge assembly includes a staple cartridge, a cartridge carrier, and a strain gauge. The cartridge carrier includes an elongated support channel configured to receive the staple cartridge, the elongated support channel defined by an inner first surface and a pair of inner second surfaces. The inner first surface includes a recess defined therein, and the strain gauge is disposed within the recess. The handle assembly includes a power-pack configured to receive sensor data from the strain gauge of the end effector and to control a function of the end effector in response to the sensor data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/687,846 filed Jun. 21, 2018, the entire disclosure of which is incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates generally to surgical devices. More particularly, the present disclosure relates to powered handheld electromechanical instruments including strain gauges.

BACKGROUND

A number of surgical device manufacturers have developed product lines with proprietary powered drive systems for operating and/or manipulating surgical devices. In many instances the surgical devices include a powered handle assembly, which is reusable, and a disposable end effector or the like that is selectively connected to the powered handle assembly prior to use and then disconnected therefrom following use in order to be disposed of or, in some instances, sterilized for re-use.

Sensors may be used to enhance control of functions in powered surgical devices, such as surgical stapling devices. For example, some powered surgical stapling devices use current sensors to detect electrical current draw from a motor of the device, or load reading sensors along a drive assembly of the device, as an indicator of the forces required to compress tissue, to form staples, and/or to transect the tissue. Load reading sensors can be used to detect pre-set loads and cause the powered surgical stapling device to react thereto. For example, during clamping of thick tissue, the load will rise to a pre-determined limit where the device can slow clamping to maintain the clamping force as the tissue relaxes. This allows for clamping of thick tissue without damage to such tissue (e.g., serosa tears). Data collected from these sensors may also be used to control the speed of firing, which has been shown to improve staple formation by slowing the stapler speed and lowering the firing force. The data may also be used in other aspects of the stapling process, such as detecting end stop and emergency stopping to prevent damage to the end effector.

It would be desirable to reduce or minimize the cost of assembling sensors, such as strain gauges, into powered surgical devices and, in particular, into disposable powered surgical devices or disposable components of such devices (e.g., an end effector), by, for example, simplifying the assembly process and/or minimizing the total number of components and/or connections required for assembly.

SUMMARY

A surgical device in accordance with aspects of the present disclosure includes an end effector and a handle assembly operably coupled to the end effector. The end effector includes an anvil assembly and a cartridge assembly pivotally coupled to one another. The cartridge assembly includes a staple cartridge, a cartridge carrier, and a strain gauge. The cartridge carrier includes an elongated support channel configured to receive the staple cartridge, the elongated support channel defined by an inner first surface and a pair of inner second surfaces. The inner first surface includes a recess defined therein, and the strain gauge is disposed within the recess of the cartridge carrier. The handle assembly includes a power-pack configured to receive sensor data from the strain gauge of the end effector and to control a function of the end effector in response to the sensor data.

The recess of the cartridge carrier may include a first portion extending longitudinally along a majority of the length of the cartridge carrier. The strain gauge may be secured to the first portion of the recess. The recess of the cartridge carrier may include a second portion extending from the first portion at an angular orientation relative thereto and open to one of the pair of inner second surfaces of the cartridge carrier. A flex circuit may be disposed within the second portion of the cartridge carrier and extend distally along the respective one of the pair of inner second surface of the cartridge carrier.

The strain gauge may be embedded within the flex circuit. The flex circuit may include a first region including resistor traces forming the strain gauge, and a second region including conductive traces coupled to the strain gauge. The flex circuit may include a first dielectric layer, a resistive layer disposed over the first dielectric layer, a conductive layer disposed over the resistive layer. The resistive layer may extend an entire length of the first dielectric layer. The resistive layer may include resistor traces patterned in a first region of the flex circuit and a continuous plane of resistive material in a second region of the flex circuit. The conductive layer may be disposed over the resistive layer with the resistor traces masked from the conductive layer.

The end effector may further include a microcontroller coupled to a memory. The microcontroller may be electrically coupled to the strain gauge and configured to receive sensor data from the strain gauge, and the memory may be configured to store the sensor data.

An end effector in accordance with aspects of the present disclosure includes an anvil assembly and a cartridge assembly pivotally coupled to one another. The cartridge assembly includes a staple cartridge, a cartridge carrier, and a strain gauge. The cartridge carrier includes an elongated support channel configured to receive the staple cartridge, the elongated support channel defined by an inner first surface and a pair of inner second surfaces. The inner first surface includes a recess defined therein, and the strain gauge is disposed within the recess of the cartridge carrier.

The recess of the cartridge carrier may include a first portion extending longitudinally along a majority of the length of the cartridge carrier. The strain gauge may be secured to the first portion of the recess. The recess of the cartridge carrier may include a second portion extending from the first portion at an angular orientation relative thereto and open to one of the pair of inner second surfaces of the cartridge carrier. A flex circuit may be disposed within the second portion of the cartridge carrier and extend distally along the respective one of the pair of inner second surfaces of the cartridge carrier.

The strain gauge may be embedded within the flex circuit. The flex circuit may include a first region including resistor traces forming the strain gauge, and a second region including conductive traces coupled to the strain gauge. The flex circuit may include a first dielectric layer, a resistive layer disposed over the first dielectric layer, a conductive layer disposed over the resistive layer. The resistive layer may extend an entire length of the first dielectric layer. The resistive layer may include resistor traces patterned in a first region of the flex circuit and a continuous plane of resistive material in a second region of the flex circuit. The conductive layer may be disposed over the resistive layer with the resistor traces masked from the conductive layer.

The end effector may further include a microcontroller coupled to a memory. The microcontroller may be electrically coupled to the strain gauge and configured to receive sensor data from the strain gauge, and the memory may be configured to store the sensor data.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure are described herein with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a surgical device including a handle housing, an adapter assembly, and an end effector in accordance with an embodiment of the present disclosure;

FIG. 2A is a perspective view, with parts separated, of the handle housing of the surgical device of FIG. 1;

FIG. 2B is a perspective view, with parts separated, of a motor assembly and a control assembly of the handle housing of FIG. 2A;

FIG. 3A is a perspective view of the adapter assembly of the surgical device of FIG. 1;

FIG. 3B is a perspective view of an electrical assembly of the adapter assembly of FIG. 3A;

FIG. 3C is a cutaway view of a distal portion of the adapter assembly of FIG. 3A;

FIG. 3D is a perspective view of an annular member and a switch of the adapter assembly of FIG. 3C;

FIG. 4A is a perspective view of the end effector of the surgical device of FIG. 1;

FIG. 4B is a perspective view of an anvil assembly and a drive assembly of the end effector of FIG. 4A;

FIG. 4C is a perspective view, with parts separated, of the end effector of the surgical device of FIG. 4A;

FIG. 4D is a perspective view of a cartridge carrier of the end effector of FIG. 4C;

FIG. 4E is a top view of the cartridge carrier of FIG. 4D including a flex circuit and a strain gauge secured thereto in accordance with an embodiment of the present disclosure;

FIG. 4F is a perspective view of an inner housing of the end effector of FIG. 4A;

FIG. 5A is a perspective view of the strain gauge and the flex circuit of FIG. 4E;

FIG. 5B is a top view of the flex circuit of FIG. 5A;

FIG. 6A is a top view of a flex circuit and a strain gauge in accordance with another embodiment of the present disclosure; and

FIG. 6B is a perspective view, with parts separated, of the flex circuit of FIG. 6A, showing layers of the flex circuit in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. Throughout this description, the term “proximal” refers to a portion of a device, or component thereof, that is closer to a user, and the term “distal” refers to a portion of the device, or component thereof, that is farther from the user.

Turning now to FIG. 1, a surgical device 10, in accordance with an embodiment of the present disclosure, is in the form of a powered handheld electromechanical instrument. The surgical device 10 includes a handle assembly 100, an adapter assembly 200, and a tool assembly or end effector 300. The handle assembly 100 is configured for selective connection with the adapter assembly 200 and, in turn, the adapter assembly 200 is configured for selective connection with the end effector 300.

The handle assembly 100, the adapter assembly 200, and the end effector 300 will only further be described to the extent necessary to disclose aspects of the present disclosure. For a detailed description of the structure and function of exemplary handle and adapter assemblies, and end effectors, reference may be made to commonly owned U.S. Patent Appl. Pub. No. 2016/0310134 (“the '134 Publication”), the entire content of which is incorporated herein by reference.

With reference now to FIG. 2A, the handle assembly 100 includes an outer housing shell 112, including a proximal half-section 112 a and a distal half-section 112 b, and an inner handle housing 114 disposed within the outer housing shell 112. The outer housing shell 112 includes a plurality of actuators 116 (e.g., finger-actuated control buttons, knobs, toggles, slides, interfaces, and the like) for activating various functions of the surgical device 10 (FIG. 1), and the inner handle housing 114 houses a power-pack 120 configured to power and control various operations of the surgical device 10.

As shown in FIGS. 2A and 2B, the power-pack 120 includes a rechargeable battery 122 configured to supply power to any of the electrical components of the surgical device 10, a battery circuit board 124, and a controller circuit board 126. The controller circuit board 126 includes a motor controller circuit board 126 a, a main controller circuit board 126 b, and a first ribbon cable 126 c interconnecting the motor controller circuit board 126 a and the main controller circuit board 126 b. The motor controller circuit board 126 a is communicatively coupled with the battery circuit board 124 enabling communication therebetween and between the battery circuit board 124 and the main controller circuit board 126 b.

The main controller circuit board 126 a includes a 1-wire communication system including three 1-wire buses which enables communication between the power-pack 120 and the battery 122, the power-pack 120 and the adapter assembly 200 (FIG. 1), and the power-pack 120 and the outer shell housing 112. Specifically, with regard to communication between the power-pack 120 and the adapter assembly 200, the 1-wire bus establishes a communication line between a 1-wire master chip of the main controller circuit board 126 b and a 1-wire memory chip of a circuit board 224 (FIG. 3B) of the adapter assembly 200. This communication line allows for calibration and communication of data and control signals between the handle assembly 100 and the adapter assembly 200, and enables information stored in the 1-wire memory chip of the circuit board 224 of the adapter assembly 200 to be accessed, updated, and/or incremented by the power-pack 120.

The power-pack 120 further includes motors 128 (e.g., a first motor 128 a, a second motor 128 b, and a third motor 128 c) each electrically connected to the controller circuit board 126 and the battery 122. The motors 128 a, 128 b, 128 c are disposed between the motor controller circuit board 126 a and the main controller circuit board 126 b. Each of the motors 128 a, 128 b, 128 c includes a respective motor shaft 129 a, 129 b, 129 c extending therefrom for transmitting rotative forces or torque.

Each of the motors 128 a, 128 b, 128 c is controlled by a respective motor controller (not shown) disposed on the motor controller circuit board 126 a, and each motor controller is electrically coupled to a main controller or master chip disposed on the main controller circuit board 126 b via the first ribbon cable 126 c which connects the motor controller circuit board 126 a with the main controller circuit board 126 b. The master chip is also coupled to memory, which is also disposed on the main controller circuit board 126 b.

Each of the motor 128 a, 128 b, 128 c is supported on a motor bracket 130 such that the motor shafts 129 a, 129 b, 129 c are rotatably disposed within respective apertures of the motor bracket 130. The motor bracket 130 rotatably supports three rotatable drive connector sleeves 132 a, 132 b, 132 c that are keyed to respective motor shafts 129 a, 129 b, 129 c of the motors 128 a, 128 b, 128 c. The drive connector sleeves 132 a, 132 b, 132 c non-rotatably receive proximal ends of respective coupling shafts 142 a, 142 b, 142 c of a plate assembly 140 of the handle assembly 100, when the power-pack 120 is disposed within the outer shell housing 112.

The motor bracket 130 also supports an electrical adapter interface receptacle 134. The electrical adapter interface receptacle 134 is in electrical connection with the main controller circuit board 126 b by a second ribbon cable 126 d. The electrical adapter interface receptacle 134 defines a plurality of electrical slots for receiving respective electrical contacts or blades extending from a pass-through connector 144 of the plate assembly 140 of the handle assembly 100.

Rotation of the motor shafts 129 a, 129 b, 129 c by respective motors 128 a, 128 b, 128 c function to drive shafts and/or gear components of the adapter assembly 200 in order to perform the various operations of the surgical device 10. In particular, the motors 128 a, 128 b, 128 c of the power-pack 120 are configured to drive shafts and/or gear components of the adapter assembly 200 in order to selectively move a tool assembly 320 (FIG. 4A) of the end effector 300 relative to a proximal body portion 310 (FIG. 4A) of the end effector 300, to rotate the end effector 300 about a longitudinal axis “X” (FIG. 4A), to move a cartridge assembly 340 (FIG. 4A) relative to an anvil assembly 330 (FIG. 4A) of the end effector 300, and/or to fire staples from within the cartridge assembly 340 of the end effector 300.

Referring now to FIG. 3A, the adapter assembly 200 includes an outer knob housing or connector housing 202 and an outer tube or sleeve 204 extending distally from the outer knob housing 202 and terminating at a distal cap 206. The outer knob housing 202 is configured for operable connection to the handle assembly 100 (FIG. 1) and the outer tube 204 is configured for operable connection to the end effector 300 (FIG. 1).

Rotatable connector sleeves 210 a, 210 b, 210 c are disposed within the outer knob housing 202 and are configured and adapted to mate, through a keyed and/or substantially non-rotatable interface, with respective coupling shafts 142 a, 142 b, 142 c (FIG. 2A) of the plate assembly 140 of the handle housing 100 such that rotation of each of the coupling shafts 142 a, 142 b, 142 c causes a corresponding rotation of the corresponding connector sleeve 210 a, 210 b, 210 c of the adapter assembly 200. The mating of the coupling shafts 142 a, 142 b, 142 c of the handle assembly 100 with the connector sleeves 210 a, 210 b, 210 c of the adapter assembly 200 allows rotational forces to be independently transmitted via each of the three respective connector interfaces. The coupling shafts 142 a, 142 b, 142 c of the handle assembly 100 are configured to be independently rotated by respective motors 128 a, 128 b, 128 c (FIG. 2B) such that rotational force(s) are selectively transferred from the motor(s) 128 a, 128 b, 128 c of the handle assembly 100 to the adapter assembly 200.

Adapter assembly 200 includes a plurality of force/rotation transmitting/converting assemblies (not shown), each disposed within an inner housing assembly (not shown) of the outer knob housing 202 and the outer tube 204. Each force/rotation transmitting/converting assembly is configured and adapted to transmit/convert a speed/force of rotation (e.g., increase or decrease) of the coupling shafts 142 a, 142 b, 142 c (FIG. 2A) of the handle assembly 100 before transmission of such rotational speed/force to the end effector 300.

Specifically, each force/rotation transmitting/converting assembly is configured and adapted to transmit or convert a rotation of the first, second and third coupling shafts 142 a, 142 b, 142 c of the handle assembly 100 into: axial translation of an articulation bar (not shown) of the adapter assembly 200 to effectuate articulation of the end effector 300 (FIG. 1); a rotation of a ring gear (not shown) of the adapter assembly 200 to effectuate rotation of the adapter assembly 200, and thus, the end effector 300; or axial translation of a distal drive member (not shown) of the adapter assembly 200 to effectuate closing, opening, and firing of the end effector 300.

As shown in FIG. 3B, in conjunction with FIG. 3A, an electrical assembly 220 is supported on and in outer knob housing 202. The electrical assembly 220 includes a plurality of electrical contact blades 222 supported on a circuit board 224 for electrical connection to pass-through connector 144 (FIG. 2A) of the plate assembly 140 of the handle assembly 100. The electrical assembly 220 also includes a strain gauge 226 electrically connected to the circuit board 224 for closed-loop feedback of firing/clamping loads exhibited by the adapter assembly 200 and regulated by the power-pack 120 (FIG. 2A), which sets the speed current limit on the appropriate motor 128 a, 128 b, 128 c (FIG. 2B).

The circuit board 224 includes a memory configured to store data relating to the adapter assembly 200 such as unique ID information (electronic serial number); type information; status information; whether an end effector has been detected, identified, and verified; usage count data; and assumed autoclave count data. The electrical assembly 220 serves to allow for calibration and communication of information (e.g., identifying information, life-cycle information, system information, force information) to the main controller circuit board 126 b (FIG. 2A) of the power-pack 120 via the electrical adapter interface receptacle 134 (FIG. 2B) of the power-pack 120 of the handle assembly 100.

With reference now to FIG. 3C, in conjunction with FIG. 3A, the adapter assembly 200 further includes a switch 230, a sensor link or switch actuator 240, and an annular member 250, each of which is disposed within a distal portion 204 a of the outer tube 204. The switch 230 is configured to toggle in response to a coupling of the end effector 300 (FIG. 1) to the outer tube 204. The switch 230 is mounted on a printed circuit board 232 that is electrically connected with the controller circuit board 126 (FIG. 2A) of the power-pack 120 of the handle housing 100. The switch 230 is configured to couple to a memory 352 (FIG. 4F) of the end effector 300. The memory 352 of the end effector 300 is configured to store data pertaining to the end effector 300 and is configured to provide the data to the controller circuit board 126 (FIG. 2A) of the handle assembly 100 in response to coupling of the end effector 300 to the outer tube 204. The power-pack 120 monitors communication between the power-pack 120 and the adapter assembly 200 and is able to detect that the end effector 300 is engaged to or disengaged from the distal portion 204 a of the outer tube 204 by recognizing that the switch 230 has been toggled.

The switch actuator 240 is slidingly disposed within the distal portion 204 a of the outer tube 204. The switch actuator 240 is longitudinally movable between proximal and distal portions, and toggles the switch 230 during movement between the proximal and distal positions.

As shown in FIGS. 3C and 3D, the annular member 250 is rotatably disposed within an inner housing 208 which, in turn, is disposed within the outer tube 204 (FIG. 3A). The annular member 250 extends from a proximal end 250 a to a distal end 250 b, and defines a cylindrical passageway 251 therethrough configured for disposal of an outer housing 312 (FIG. 4A) of the end effector 300. The annular member 250 includes a longitudinal bar 252 interconnecting a first ring 254 at the proximal end 250 a of the annular member 250 and a second ring 256 at the distal end 250 b of the annular member 250. The first ring 254 includes a pair of electrical contacts 258 electrically coupled to the switch 230 via wires 234, the wires 234 extending to the electrical assembly 220 (FIG. 3B) to electrically couple the switch 230 with the circuit board 224 of the adapter assembly 200. The electrical contacts 258 are configured to engage corresponding electrical contacts 356 (FIG. 4F) of the end effector 300, such that the switch 240 and the annular member 250 are capable of transferring data pertaining to the end effector 300 therebetween, ultimately for communication with the power-pack 120, as described in further detail below.

Referring now to FIG. 4A, the end effector 300 is in the form of a single use loading unit. It should be understood, however, that other types of end effectors may also be used with the surgical device 10 of the present disclosure including, for example, end-to-end anastomosis loading units, multi-use loading units, transverse loading units, and curved loading units. As discussed below, the particular end effector 300 utilized with the surgical device 10 is recognized by the power-pack 120 (FIG. 2A) of the handle assembly 100 to enable appropriate operation thereof.

The end effector 300 includes a proximal body portion 310 and a tool assembly 320. The proximal body portion 310 is releasably attachable to the distal cap 206 (FIG. 3A) of the adapter assembly 200 and the tool assembly 320 is pivotally attached to the proximal body portion 310. The tool assembly 320 includes an anvil assembly 330 and a cartridge assembly 340. The anvil and cartridge assemblies 330, 340 are pivotal with respect to each other such that the tool assembly 320 is movable between an open or unclamped position and a closed or clamped position.

As shown in FIGS. 4A-4C, the anvil assembly 330 includes an anvil plate 332 and a cover plate 334 having an inner surface 334 a secured over the anvil plate 332 such that the cover plate 334 defines an outer surface 334 b of the anvil assembly 330. The anvil plate 332 includes a tissue contacting surface 336 including a plurality of staple forming pockets 336 a and a longitudinal slot 336 b defined therein.

The cartridge assembly 340 includes a staple cartridge 342 and a cartridge carrier 344. The cartridge carrier 344 defines an elongated support channel 344 a configured and dimensioned to selectively receive the staple cartridge 342 therein such that the cartridge carrier 344 defines an outer surface 344 b of the cartridge assembly 340. The staple cartridge 342 includes a tissue contacting surface 346 defining staple pockets or retention slots 346 a formed therein for receiving a plurality of fasteners or staples (not shown) and a longitudinal slot 346 b formed in and extending along a substantial length of the staple cartridge 342.

The proximal body portion 310 of the end effector 300 includes a drive assembly 315 operably associated with and slidably disposable between the anvil and cartridge assemblies 330, 340 for driving the ejection of staples (not shown) from the cartridge assembly 340 of the tool assembly 320, and an articulation link (not shown) for effectuating an articulation of the tool assembly 320. The drive assembly 315 includes an elongated drive beam 316 and an I-beam 317 having a central wall portion 317 a including a knife 317 b. The knife 317 b can travel through the longitudinal slots 336 b, 346 b defined in the tissue contacting surfaces 336, 346 of the anvil and cartridge assemblies 330, 340, between the staple forming pockets 336 a and the retention slots 346 a also defined in the respective tissue contacting surfaces 336, 346 to longitudinally cut stapled tissue that is grasped between the tissue contacting surfaces 336, 346 of the anvil and cartridge assemblies 330, 340.

As shown in FIGS. 4C and 4D, the elongated support channel 344 a of the cartridge carrier 344 is defined by an inner first or bottom surface 348 a and inner second or side surfaces 348 b. The inner bottom surface 348 a includes a recess 349 defined therein having a first portion 349 a that extends longitudinally along a majority of the length of the cartridge carrier 344, and a second portion 349 b disposed within a proximal portion 344 c of the cartridge carrier 344 that extends at an angular relationship relative to the first portion 349 a (e.g., substantially orthogonal thereto) and open to one of the inner side surfaces 348 b of the cartridge carrier 344. As shown in FIGS. 4D and 4E, the recess 349 is configured to receive a flex circuit or cable 400 and a strain gauge 450 therein. It is envisioned that the recess 349 may have other configurations that are complementary with the size and shape of a flex cable and/or a strain gauge positioned therein.

As shown in FIG. 4E, the strain gauge 450 is positioned within the first portion 349 a of the recess 349 and secured thereto, for example, with an adhesive. The flex circuit 400 is electrically coupled to the strain gauge 450 and extends proximally through part of the first portion 349 a of the recess 349, through the second portion 349 b of the recess 349, along the inner side surface 348 b of the cartridge carrier 344, and proximally along an inner wall (not shown) of the proximal portion 310 (FIG. 4A) of the end effector 300. The flex circuit 400 is secured within the recess 349, the inner side surface 348 b of the cartridge carrier 344, and/or to the inner wall of the proximal portion 310 of the end effector 300, for example, with an adhesive. The flex circuit 400 is flexible so that it may bend, curve, or otherwise fit the contours within the end effector 300 to help route signals through the tight/limited space available within the end effector 300.

With reference now to FIG. 4F, in conjunction with FIG. 4A, the end effector 300 further includes an outer housing 312 and an inner housing 314 disposed within the outer housing 312. A proximal end of the outer housing 312 is sized and dimensioned to be inserted through the distal cap 206 (FIG. 3A) of the adapter assembly 200 to engage the adapter assembly 200.

The end effector 300 includes a microcontroller 350 and a memory 352, each of which is disposed within or on the inner housing 314. The microcontroller 350 is electrically coupled to the strain gauge 450 via the flex circuit 400. The microcontroller 350 is configured to receive and/or measure sensor data (e.g., electrical signals) from the strain gauge 450 and record them in the memory 352. The memory 352 includes a memory chip 354 and a pair of electrical contacts 356 electrically connected to the memory chip 354. The memory 352 is configured to store the sensor data received from the microcontroller 250. The sensor data may include, for example, stress measurements along the cartridge assembly 340 which, in turn, may be converted, via an algorithm, into corresponding tissue stress measurements of the tissue disposed between the anvil and cartridge assemblies 330, 340 of the end effector 300.

The memory chip 354 is also configured to store one or more parameters related to the end effector 300. The parameters include, for example, a serial number of a loading unit, a type of loading unit, a size of loading unit, a staple size, information identifying whether the loading unit has been fired, a length of a loading unit, maximum number of uses of a loading unit, and combinations thereof. The memory chip 354 is configured to communicate to the handle assembly 100 the sensor data and/or parameters of the end effector 300, as described above, via the electrical contacts 356, upon engagement of the end effector 300 with the adapter assembly 200, as described below. The sensor data and/or parameters may be processed in the controller circuit board 126 of the handle assembly 100, or in some other remote processor or the like.

The electrical contacts 356 are disposed on an outer surface of the inner housing 314 and are configured to engage the electrical contacts 258 (FIG. 3D) of the annular member 250 of the adapter assembly 200 upon insertion of the end effector 300 into the adapter assembly 200. This connection between the electrical contacts 356 of the end effector 300 and the electrical contacts 258 of the adapter assembly 200 allows for communication between the memory chip 354 of the end effector 300 and the controller circuit board 126 (FIG. 2A) of the power-pack 120 of the handle assembly 100.

With reference now to FIGS. 5A and 5B, the flex circuit 400 includes a body or substrate 410 suitable for supporting and/or electrically connecting electronic components thereto. The electronic components may be, for example, surface mount technology and/or through-hole technology, including, for example, integrated circuits (e.g., microchips, microcontrollers, microprocessors), resistors, amplifiers, inductors, capacitors, sensing elements (e.g., optical sensors, pressure sensors, capacitive sensors), buttons, switches, circuit boards, electrical connectors, cables, and/or wires, among other elements or circuitry within the purview of those skilled in the art. As discussed above, the flex cable 400 electrically interconnects the microcontroller 350 (FIG. 4F) and the strain gauge 450.

The substrate 410 is formed from one or more layers or sheets of dielectric material 420 (also referred to herein as dielectric layer(s)) and one or more layers of conductive material 430 (also referred to herein as conductive layer(s)) that form conductive traces 432 in the substrate 410. The dielectric layers 420 may be formed from polymers such as, for example, polyimides, acrylics, or polyesters, among other flexible and temperature resistant or electrically insulative materials within the purview of those skilled in the art. The conductive layers 430 may be formed from metals such as, for example, copper, gold, nickel, or aluminum, among other materials within the purview of those skilled in the art having low resistivity and that can route signals between electronic components of the flex circuit 400, such as between the strain gauge 450 and the microcontroller 350 (FIG. 4F). Vias (not shown) may be used to interconnect conductive traces 432 through different layers of the flex circuit 400.

The dielectric and conductive layers 420, 430 of the substrate 410 may be joined to one another by, for example, laminating, welding, and/or using adhesives, among other methods and materials within the purview of those skilled in the art. While the flex circuit 400 is shown as a single sided flex circuit, it should be understood that the substrate 410 may be configured to allow for the fabrication of single or double sided flex circuits, multilayer flex circuits, or rigid flex circuits.

Electrical contact regions 434 are disposed at terminal ends of the conductive traces 432 defined through the substrate 410 on a first side 400 a of the flex circuit 400. Each of the electrical contact regions 434 includes one or more conductive contact points (e.g., solder pads, conductive adhesive, etc.) to which electrical components are attached or otherwise coupled to the substrate 410. The substrate 410 includes a first electrical contact region 434 a disposed at a first or distal end 410 a of the substrate 410 which is aligned and soldered to the strain gauge 450, and a second electrical contact region 434 b disposed at a second or proximal end 410 b of the substrate 410 to be electrically coupled to the microcontroller 350 (FIG. 4F). It should be understood that while the flex circuit 400 is shown including two electrical contact regions 434 a, 434 b, the flex circuit may have any number of electrical contact regions depending upon the desired configuration and functionality of the flex circuit, as is within the purview of those skilled in the art.

The strain gauge 450 includes a polymeric carrier 460 (e.g., one or more layers of dielectric material) and one or more layers of resistive material 470 (also referred to herein as resistive layer(s)) that are patterned to form resistor traces 472 within the polymeric carrier 460. The resistive layers 470 may be formed from metal alloys such as, for example, constantan, which is a copper nickel alloy that exhibits changes in resistance when exposed to strain and relatively minimal changes in resistance as a function of temperature, among other materials within the purview of those skilled in the art having high resistivity, a negative thermal coefficient of resistance, and/or good mechanical properties for measuring strain.

The resistor traces 472 form or are coupled to a resistance bridge, such as a Wheatstone bridge (e.g., a quarter bridge, a half bridge, a full bridge), that can read a strain response of the structure to which the strain gauge 450 is attached. With reference again to FIG. 4E, the strain gauge 450 is positioned within the first portion 349 a of the recess 349 of the cartridge carrier 344 and is configured to measure deformation of the cartridge carrier 344 due to forces exerted on the cartridge assembly 340 (FIG. 4A) under a loading condition such as, for example, during clamping of tissue within the tool assembly 320 and/or during firing of the end effector 300. The strain experienced by the cartridge carrier 344 is directly transferred to the strain gauge 450 which responds with a change in resistance, the flex circuit 400 providing the excitation voltage to the strain gauge 450 and the return path for sensor data (e.g., voltage readings).

With reference now to FIG. 6A, a flex circuit 500 includes a strain gauge 550 embedded therein. The integration of the strain gauge 550 into the flex circuit 500 removes the need for a solder connection or wire bond between the strain gauge 550 and the flex circuit 500 thereby minimizing the spaced needed in the cartridge carrier 344 (FIG. 4E) to get signal and power to the strain gauge 550, reducing potential failure of attachment between the flex circuit 500 and the strain gauge 550, and/or simplifying the assembly process.

The flex circuit 500 includes a substrate 510 including one or more dielectric layers 520, one or more conductive layers 530, and one or more resistive layers 540. Resistor traces 542 are formed in a first region 502 of the flex circuit 500 which corresponds with the first portion 349 a (FIG. 4D) of the recess 349 of the cartridge carrier 344. The first region 502 of the flex circuit 500 forms the strain gauge 550 such that compression and/or extension of the cartridge carrier 344 changes the length or deforms the resistive layer(s) 540 on the flex circuit 500. As discussed above, using a resistance bridge, such as a Wheatstone bridge, the changes in the resistance are measured. Conductive traces 532 are formed in a second region 504 of the flex circuit 500 to provide a signal path to and from the first region 502 of the flex circuit 500 such as, for example, to and from the microcontroller 350 (FIG. 4F) coupled to the second region 504 of the flex circuit 500 at electrical contact region 534.

With reference now to FIG. 6B, the flex circuit 500 is formed by placing a resistive layer 540 onto a first dielectric layer 520 a. The resistive layer 540 may extend through both first and second regions 502, 504 of the flex circuit 500 (e.g., the resistive layer may extend the entire length of the flex circuit). The resistive layer 540 in the first region 502 of the flex circuit 500 is patterned to form the resistor traces 542, and the resistive layer 540 in the second region 504 of the flex circuit 500 is a continuous plane of material. The first region 502 is then masked and a conductive layer 530 is placed over the resistive layer 540. The conductive layer 530 is patterned to form the conductive traces 532 in the flex circuit 500. A second dielectric layer 520 b is then placed over the conductive layer 530. As the conductive and resistive layers 530, 540 are disposed adjacent to and in contact with each other, and the resistive layer 540 has a higher resistance than the conductive layer 530, current will only flow through the conductive layer 530 and the resistive layer 540 changes in resistance as the flex circuit 500 deforms.

In operation of the surgical device 10, upon initial insertion of the end effector 300 into the adapter assembly 200, the switch actuator 240 remains disengaged from the switch 230. With the switch 230 in the unactuated state, there is no electrical connection established between the memory 352 of the end effector 300 and the controller circuit board 126 of the handle assembly 100. Upon a rotation of the end effector 300, the end effector 300 engages the adapter assembly 200 and moves the switch actuator 240 distally, which toggles the switch 230 to actuate the switch 230. With the switch 230 in the actuated state, an electrical connection is established between the memory chip 354 of the end effector 300 and the controller circuit board 126 of the handle assembly 100, through which information about the end effector 300 is communicated to the controller circuit board 126 of the handle assembly 100. Upon both the actuation of the switch 230 and the establishment of a wiping contact between the electrical contacts 356 of the inner housing 314 of the end effector 300 and the electrical contacts 258 of the annular member 250 of the adapter assembly 200, the handle assembly 100 is able to detect that the end effector 300 is engaged with the adapter assembly 200 and to identify one or more parameters of the end effector 300 and/or to process the sensor data from the strain gauge 450, 550 of the end effector 300. Accordingly, the power-pack 120 is capable of reading the information stored in the memory 352 of the end effector 300 via the adapter assembly 200.

With the end effector 300 engaged to the adapter assembly 200, the strain gauge 450, 550 of the end effector 300 detects and/or measures mechanical behaviors and/or properties of the tool assembly 320 in real time during a surgical procedure. The sensor data is transmitted to the microcontroller 350 via the flex circuit 400, 500 for processing, stored in the memory 352, and ultimately transferred to the power-pack 120 of the handle assembly 100 via the adapter assembly 200 along the 1-wire bus, or other communication protocol. The power-pack 120 collects and processes the sensor data in real time, and transmits electrical control signals to the motors 128 a, 128 b, 128 c of the handle assembly 100 to control a function of the surgical device 10 (e.g., to change an operating parameter, such as pre-compression time, speed of firing, etc.). The mechanical behaviors and/or properties of the tool assembly 320 detected/measured by the strain gauge 450, 550 are then converted and/or correlated to real time, or near real time, behaviors and/or properties of the target tissue clamped in the tool assembly 320.

For example, in a method of using the surgical device 10 of the present disclosure, the end effector 300 is placed at a desired surgical site and the anvil assembly 330 and the cartridge assembly 340 are approximated and clamped to grasp target tissue between the respective tissue contacting surfaces 336, 346 of the anvil and cartridge assemblies 330, 340. The strain gauge 450, 550 measures stress in the cartridge assembly 340, and in turn, measures stress in the target tissue. Specifically, the resistance of the strain gauge 450, 550 is sent to the microcontroller 350 of the end effector 300 which, in turn, processes the resistance to calculate a force or pressure on the strain gauge 450, 550 which, ultimately, is transmitted to the power-pack 120 of the handle assembly 100 via the adapter assembly 200. The power-pack 120 processes the sensor data and controls the wait time between clamping of the target tissue and firing of staples from the cartridge assembly 340 until a stress on the target tissue is at a value within an acceptable range of values. Accordingly, the microcontroller 350 may continuously or intermittently monitor the strain gauge 450, 550 for collection of the sensor data. The handle assembly 100 may provide a visual or audible indication to a user that the surgical device 10 is ready for firing. The wait time is beneficial to minimize or avoid negative acute events related to excess stress in the target tissue, such as bruising, tearing, and bleeding. The strain gauge 450, 550 controls the firing of the surgical device 10 to keep the target tissue stress within an ideal stress region which is beneficial for sealing the target tissue, allowing perfusion for healing, providing hemostasis and pneumostasis, and/or preventing leakage.

It should be understood that various modifications may be made to the embodiments of the presently disclosed surgical device. For example, the end effector of the present disclosure may be modified to additionally or alternatively include a strain gauge/flex circuit in the anvil assembly. As another example, it should be understood that the handle assembly, the adapter assembly, and/or the end effector may be modified depending on the desired use of the surgical device of the present disclosure. For example, handle assemblies, end effectors and/or adapter assemblies of the present disclosure may be configured to perform, for example, endoscopic gastro-intestinal anastomosis (EGIA) procedures or end-to-end anastomosis (EEA) procedures. For a detailed description of the structure and function of exemplary handle assemblies, adapter assemblies, and end effectors, reference may be made to commonly owned U.S. Patent Publication No. 2016/0296234 (“the '234 Publication”), the entire content of which is incorporated herein by reference, and the '134 Publication, the entire content of which was previously incorporated herein by reference. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure. 

What is claimed is:
 1. A surgical device, comprising: an end effector including an anvil assembly and a cartridge assembly pivotally coupled to one another, the cartridge assembly including: a staple cartridge; a cartridge carrier including an elongated support channel configured to receive the staple cartridge, the elongated support channel defined by an inner first surface and a pair of inner second surfaces, the inner first surface including a recess defined therein; and a strain gauge disposed within the recess of the cartridge carrier; and a handle assembly operably coupled to the end effector, the handle assembly including a power-pack configured to receive sensor data from the strain gauge of the end effector and to control a function of the end effector in response to the sensor data.
 2. The surgical device according to claim 1, wherein the recess of the cartridge carrier includes a first portion extending longitudinally along a majority of the length of the cartridge carrier, the strain gauge secured to the first portion of the recess.
 3. The surgical device according to claim 2, wherein the recess of the cartridge carrier includes a second portion extending from the first portion at an angular orientation relative thereto and open to one of the pair of inner second surfaces of the cartridge carrier.
 4. The surgical device according to claim 3, wherein the end effector includes a flex circuit disposed within the second portion of the cartridge carrier and extending distally along the respective one of the pair of inner second surfaces of the cartridge carrier.
 5. The surgical device according to claim 4, wherein the strain gauge is embedded within the flex circuit.
 6. The surgical device according to claim 5, wherein the flex circuit includes a first region including resistor traces forming the strain gauge, and a second region including conductive traces coupled to the strain gauge.
 7. The surgical device according to claim 5, wherein the flex circuit includes a first dielectric layer, a resistive layer disposed over the first dielectric layer, a conductive layer disposed over the resistive layer.
 8. The surgical device according to claim 7, wherein the resistive layer extends an entire length of the first dielectric layer, the resistive layer including resistor traces patterned in a first region of the flex circuit and a continuous plane of resistive material in a second region of the flex circuit.
 9. The surgical device according to claim 8, wherein the conductive layer is disposed over the resistive layer, the resistor traces masked from the conductive layer.
 10. The surgical device according to claim 1, wherein the end effector further includes a microcontroller coupled to a memory, the microcontroller electrically coupled to the strain gauge and configured to receive sensor data from the strain gauge, the memory configured to store the sensor data.
 11. An end effector for a surgical device, the end effector comprising: an anvil assembly; and a cartridge assembly pivotally coupled to the anvil assembly, the cartridge assembly including: a staple cartridge; a cartridge carrier including an elongated support channel configured to receive the staple cartridge, the elongated support channel defined by an inner first surface and a pair of inner second surfaces, the inner first surface including a recess defined therein; and a strain gauge disposed within the recess of the cartridge carrier.
 12. The end effector according to claim 11, wherein the recess of the cartridge carrier includes a first portion extending longitudinally along a majority of the length of the cartridge carrier, the strain gauge secured to the first portion of the recess.
 13. The end effector according to claim 12, wherein the recess of the cartridge carrier includes a second portion extending from the first portion at an angular orientation relative thereto and open to one of the pair of inner second surfaces of the cartridge carrier.
 14. The end effector according to claim 13, wherein the end effector includes a flex circuit disposed within the second portion of the cartridge carrier and extending distally along the respective one of the pair of inner second surfaces of the cartridge carrier.
 15. The end effector according to claim 14, wherein the strain gauge is embedded within the flex circuit.
 16. The end effector according to claim 15, wherein the flex circuit includes a first region including resistor traces forming the strain gauge, and a second region including conductive traces coupled to the strain gauge.
 17. The end effector according to claim 15, wherein the flex circuit includes a first dielectric layer, a resistive layer disposed over the first dielectric layer, a conductive layer disposed over the resistive layer.
 18. The end effector according to claim 17, wherein the resistive layer extends an entire length of the first dielectric layer, the resistive layer including resistor traces patterned in a first region of the flex circuit and a plane of resistive material in a second region of the flex circuit.
 19. The end effector according to claim 18, wherein the conductive layer is disposed over the resistive layer, the resistor traces masked from the conductive layer.
 20. The end effector according to claim 11, further comprising a microcontroller coupled to a memory, the microcontroller electrically coupled to the strain gauge and configured to receive sensor data from the strain gauge, the memory configured to store the sensor data. 